In reply to Baron Weasel:
The paperwork is a doddle these days, now that there's no requirement for blood testing to prove that the rabies jab has taken. Basically, you need a microchip and a single rabies shot, and three weeks later you're ready to go. As others have mentioned, between 1 and 5 days prior to return, pop and see a French vet for a tablet, and all's good.
One thing I would suggest is a scalibor anti-tick collar. They're not expensive, you're likely to be going through tick country at a time of at least moderate risk, and dogs are similarly prone to tick-borne diseases as are people. It would also be useful to grab an o'tom hook before you go, and go over the dog once a day. Talk to your vet about lungworm and Giardia (from wet ground and streams), which are probably as high a risk at home as in the Vercors, but there's not much going on out there that s/he wouldn't be exposed to at home.
Hope this helps
Martin (vet)